MEMOIR ON METEORITES. 277 



Nos. 1 and 2 were separated mechanically from tlie iron; 

 No. 3 chemically. The silica, alumina, and lime were almost 

 entirely absent from ]S"o. 3, and in the other specimen they are 

 due to a siliceous mineral that I have found attached in small 

 particles to the schreibersite. There is no essential difference 

 in my results; yet in neither instance do I suppose the mineral 

 was obtained perfectly pure, although enough so, it is believed, 

 to furnish the correct chemical formula; and as from what 

 has been previously said schreibersite will be found to exist 

 in larger quantities than it was suspected, it will not be long 

 before the question of the uniformity of its composition will 

 be settled, a point of interest bearing upon the theoretical 

 consideration of meteoric stones. 



The formula of schreibersite I consider to be M 2 Fe 4 P. 



Atom. Per cent. 



Phosphorus 1 15.47 



Nickel ... 2 29.17 



Iron 4 55.36 



This mineral, although not usually much dwelt upon when 

 speaking of meteorites, is decidedly the most interesting one 

 associated with this class of bodies, even more so than the 

 nickeliferous iron. It has no representative in genus or spe- 

 cies among terrestrial minerals, and is one possessed of highly 

 interesting properties. Although among terrestrial minerals 

 phosphates are found, not a single phosphuret is known to 

 exist. So true is this that, with our present knowledge, if any 

 one thing could convince me more strongly than another of 

 the non -terrestrial origin of any natural body, it would be the 

 presence of this or some similar phosphuret. It is commonly 

 alluded to as a residue from the action of hydrochloric acid 

 upon meteoric iron, when in fact it exists in plates and frag- 

 ments of some size in almost all meteoric iron, and there is 

 reason to believe that it is never absent from any of them in 

 some form or other. What is meant by "some size" is that 

 it is in pieces large enough to be seen by the naked eye, and 

 to be detached mechanically. 



In an examination of the meteoric specimens in the Yale 

 College Cabinet more than half of them have been discov- 

 ered to contain schreibersite, visible to the eye, that had been 

 considered pyrites. Among them the large Texas meteorite 

 was examined ; and although none was visible on the surface, 



19 



